1. Field of the Invention
The present invention relates to an object-oriented processing system which is constructed using objects and which carries out prescribed processing, and a computer-aided software engineering (CASE) apparatus used for the construction of the object-oriented processing system, and more particularly to an object-oriented processing system which achieves database searching or data processing not possible with prior known systems by providing a multiple-character object that behaves as if its character changes with the passage of time or with a change in external environmental conditions, and an object-oriented CASE apparatus used for the construction of such an object-oriented processing system.
2. Description of the Related Art
In an object-oriented processing system such as an object-oriented database system or an object-oriented data processing apparatus, individual entities existing in the real world are each abstracted by an object in which a variable describing the properties of the entity and a method describing the behavior thereof are encapsulated together. System processing is then carried out by transferring messages between the user and a particular object and between objects.
In this way, according to the techniques of object-oriented architecture, a system having good visibility and good compatibility with the real world is constructed, so that a system for solving a variety of complex problems can be realized with relative ease. However, in prior known object-oriented systems, the basic idea is to define each object by endowing it with its properties and behavior in a fixed manner; therefore, in the case of an entity whose properties and/or behavior (these qualities are collectively called the character in this specification) change with time or with changing external environmental conditions such as temperature, the plurality of characters that the entity is supposed to assume have to be abstracted by different objects and different identifiers have to be assigned respectively to the different characters. This necessarily results in a large number of similar objects, leading to the problem of increased complexity of relationships among the objects. Furthermore, since a different identifier is assigned to each character of an object, it has not been possible to realize the kind of processing that enables the user to access an object without the user being aware of the change of the character caused according to the passage of time or to a change in external environmental conditions, or that can send a message to such an object and obtain a response according to the character of the object at that instant in time.
An object of the present invention is to provide an object-oriented processing system in which entities are efficiently modelled and whose characters (properties and/or behaviors) change according to the passage of time or to a change in external environments, and an object-oriented CASE apparatus which assists the development of such a system.
In an object-oriented system, objects include child objects and parent objects to which the child objects are subordinate, and these objects are linked by inheritance relationships. In this case, the properties or behavior that a child object does not have are inherited from its parent object. In prior known object-oriented systems, the inheritance relationships among objects are defined in a fixed manner. The present invention, by contrast, accomplishes the task of changing an object""s character by dynamically changing the inheritance relationship according to the passage of time or to a change in external environments.
According to the present invention, there is provided an object-oriented processing system comprising: a database which stores a plurality of objects that perform prescribed processing by transferring messages thereamong, including objects capable of accomplishing a dynamically changeable character by being linked together by a dynamically changeable character inheritance; a character inheritance setting unit which sets a character inheritance between objects according to an instruction, and thereby accomplishes a corresponding character; and a sensor input/output control unit which instructs the character inheritance setting unit to change the character according to the passage of time or to a change in an external environmental condition.
According to the present invention, there is also provided an object-oriented CASE apparatus for assisting the construction of an object-oriented processing system which comprises: a database which stores a plurality of objects that perform prescribed processing by transferring messages thereamong, including objects capable of accomplishing a dynamically changeable character by being linked together by a dynamically changeable character inheritance; a character inheritance setting unit which sets a character inheritance between objects according to an instruction, and thereby accomplishes a corresponding character; and a sensor input/output control unit which instructs the character inheritance setting unit to change the character according to the passage of time or to a change in an external environmental condition, said object-oriented CASE apparatus comprising: a character inheritance creation unit by which a plurality of selectable character inheritances are created interactively to define a plurality of selectable characters for objects, and are stored in the character inheritance setting unit; and a story definition part creation unit by which a story definition part that describes a procedure for changing the character according to the passage of time or to a change in an external environmental condition is created and stored in the sensor input/output control unit.